code: def _get_var(var, default=False):
      if var not in os.environ:
          return default
  
      val = os.environ.get(var, "0")
      trues = ["1", "true", "TRUE", "on", "ON", "yes", "YES"]
      falses = ["0", "false", "FALSE", "off", "OFF", "no", "NO"]
      if val in trues:
          return True
      if val not in falses:
          print(
              f" --- WARNING: Unexpected environment variable value `{var}={val}`. "
              f"Expected one of {trues + falses}"
          )
      return False
  
file_path: audio/docs/source/conf.py
imports: import os
  import re
  import sys
  import warnings
  from datetime import datetime
  import pytorch_sphinx_theme
  from docutils import nodes
  from sphinx import addnodes
  from sphinx.util.docfields import TypedField
  from custom_directives import CustomCardEnd, CustomCardItem, CustomCardStart, SupportedDevices, SupportedProperties
  from docutils.parsers import rst
label_desc: Use image node_id 1 for calling a global function with example usage: _get_var(var, default) and returns: False, default, True